A pulse sequence designed for robust CNOT gates in SiMOS quantum dots*

We theoretically analyze the errors in one- and two-qubit gates in a silicon MOS semiconductor double quantum dot setup [1], and present a pulse sequence which can suppress the errors in exchange coupling due to charge noise to within the acceptable rate for fault-tolerance using ideal local rotations. In practice, the overall fidelity of the pulse sequence will be limited only by the quality of the single-qubit gates available: the CNOT infidelity comes out to be ~10x the infidelity of the single-qubit operations.

For a realistic case, we model the errors and show that a naive implementation of our pulse sequence which uses uncorrected noisy one-qubit gates implemented by pulsing the ESR line can implement a perfect entangler two-qubit gate with a fidelity close to 99.9%, using experimental parameters. Our pulse sequence is simple and we expect an experimental implementation would be straightforward. We also evaluate the performance of this gate against 1/f noise, and analyze the effects of nonadiabaticy during finite rise periods, and compare our results against the existing adiabatic protocol presented in [1].


[1] M. Veldhorst et al, Nature 526, 410-414 (2015)